#include <bits/stdc++.h>

using namespace std;

int main() 
{
	int n;cin>>n;
	string s;cin>>s;
	s=" "+s;
	for(int i=1;i<=n;i++)
	{
		if(i%2==0&&i!=n&&i!=n-1) cout<<s[i]<<"-";
		else cout<<s[i];
	}
	return 0;
}
